To begin, turn your painting face down on a flat, clean surface.
Center your hinge along the desired side so that the middle of the hinge is aligned with the outermost edge of the painting’s stretcher or frame. I prefer attaching the hinge using a screwdriver to avoid splitting the wood of the stretcher.
Note: It’s important that the screws you use here are short so that they don’t puncture through the painting itself.
Attach as many screws as needed. (I used only two screws because my painting was small.)